1. Experiment to find the specific latent heat of vaporisation of water

2. Method Find the mass of the calorimeter mcal.
Half fill the calorimeter with water cooled to approximately 10 °C below room temperature. Find the mass m1 of the water plus calorimeter.
Record the temperature of the calorimeter plus water θ1.
Allow dry steam to pass into the water in the calorimeter until the temperature has risen by about 20 °C. Record the final temperature θ2 of the calorimeter plus water plus condensed steam.
Find the mass of the calorimeter plus water plus condensed steam m2.

3. msl + mscwΔθ1 = mcalccΔθ2 + mwcwΔθ2
Results
Mass of the calorimeter mcal =
Mass of the water plus calorimeter m1 =
Mass of the cooled water mw = m1 – mcal =
Temperature of the calorimeter plus water θ1 =
Final temperature of the calorimeter plus water plus condensed steam θ2 =
Fall in temperature of the steam Δθ1 = 100 °C – θ2 =
Rise in the temperature of the calorimeter plus water Δθ2= θ2 – θ1 =
Mass of the calorimeter plus water plus condensed steam m2 =
Mass of the condensed steam ms = m2 – m1 =
Calculation
msl + mscwΔθ1 = mcalccΔθ2 + mwcwΔθ2
Cc = 390J/KgK
Cw = 4180J/KgK

4. In an experiment to measure the specific latent heat of vaporisation of water, cold water was placed in a copper calorimeter. Steam was passed into the cold water until a suitable rise in temperature was achieved. The following results were obtained.
Mass of the calorimeter = 73.4 g
Mass of cold water = 67.5 g
Initial temperature of water = 10 °C
Temperature of the steam = 100 °C
Mass of steam added = 1.1 g
Final temperature of water = 19 °C
Describe how the mass of the steam was found. (9)
Using the data, calculate a value for the specific latent heat of vaporisation of water. The specific heat capacity of copper is 390 J /KgK and the specific heat capacity of water is 4180 J /KgK. (18)
Why is the rise in temperature the least accurate value? Give two ways of improving the accuracy of this value.